THE EFFECT OF CHRONIC HEAT STRESS ON THE URINARY SYSTEM PATHOLOGY OF BROILERS

Abstract

Thirty six, one day old broiler chicks were obtained from a commercial hatchery. They were brooded for 20 days before being placed in layer cages, with a wire floor, at 26-28oC, for a 7 day adaptation period. On day 28, the broilers were transferred into environmentally controlled housing, at 26-28oC, and were subjected to heat stress for 5 hrs, at a temperature of 33±1oC, each day, for 21 days. Fifteen birds were then randomly killed by
cervical dislocation for macroscopic and microscopic examination of the urinary system. The results revealed that the ureters in 9 out of 15 broilers showed a sac like expansion. The sacs were filled with urine similar to the bladder seen in mammals. The space in the renal tubular lumen increased in size with an accumulation of water. The kidneys showed generalized hemorrhagic changes especially in the renal papillae and the renal tubular and subrenal capsules. Fatty degeneration could be observed in all the renal tubular epithelium. Leukocytes accumulated in many inflammed areas in the kidneys.